Treatment vessel for straw or other light bulky material

Abstract

A method to chemically treat light weight, bulky cellulosic material including: introducing the material to an upper inlet of a substantially vertical treatment vessel; maintaining the material in the vessel at a pressure of at least 20 bar and at a temperature of at least 200° C.; treating the material with a cooking liquor in the vessel; moving the material past at least one anti-compression ring on an inside surface of the vessel, as the material moves downward through the vessel; agitating the material in the vessel, and discharging the treated material from a lower discharge port of the vessel.

1. A method to chemically treat light weight, bulky cellulosic material comprising:
 introducing the material to an upper inlet of a substantially vertical treatment vessel; 
 moving the material past at least one anti-compression ring on an inside surface of the vessel, as the material moves downward through the vessel; 
 agitating the material in the vessel via the anti-compression ring, and 
 discharging the treated material from a lower discharge port of the vessel. 
 
     
     
       2. The method of  claim 1  further comprising maintaining the material in the vessel at a pressure of at least 20 bar and at a temperature of at least 140° C. 
     
     
       3. The method of  claim 1  further comprising treating the material with a cooking liquor in the vessel. 
     
     
       4. The method of  claim 1  further comprising allowing auto-hydrolysis to occur in the material in the vessel. 
     
     
       5. The method of  claim 1  wherein the light weight, bulky cellulosic material includes at least one of straw, bagasse, corn stover, and energy crops. 
     
     
       6. The method of  claim 1  wherein the vessel is maintained at a pressure of at least 20 bar and at a temperature of at least 200° C. 
     
     
       7. The method of  claim 1  wherein the vessel is a single chamber vessel for chemically digesting the material to pulp. 
     
     
       8. The method of  claim 1  wherein the anti-compression ring is in an upper portion of the vessel. 
     
     
       9. The method of  claim 1  wherein further comprising retaining the material in the vessel for a period no greater than 30 minutes. 
     
     
       10. The method of  claim 1  wherein the treatment includes hydrolysis of the material.